A related art printed circuit board in which an optical waveguide is incorporated includes an optical element such as a vertical cavity surface emitting laser (VCSEL) or an optical module that includes the optical element.
The optical waveguide receives light emitted from the optical element at a 45-degree mirror (entrance) thereof formed at an end of a core such that the 45-degree mirror is inclined relative to the core by 45-degree. The light received at the 45-degree mirror (entrance) exits the optical waveguide from a 45-degree mirror (exit) formed at the other end of the core. Thus, an optical interconnect is realized.
An optical component is placed at a target position on a board, by, for example, being sucked by a pick and place machine, by being sucked by a flip chip bonder, or by being clamped by a mechanical chuck.
In general, a light emitting component is very small, and accordingly, use of passive alignment, in which an image of something serving as a mark on the component is recognized so as to position the component, is limited. Thus, a method so-called active alignment is used, in which the component is caused to emit light, a position where the amount of light is the largest is recognized (alignment), and the component is placed at the recognized position.
Nowadays, as transmission rates and transmission distances are increasing, in order to suppress optical losses, the diameter of the core of the optical waveguide is decreasing. The diameter of the core is, for example, 30 to 50 μm. When the diameter of the core is set to such a size, it is desirable that the positioning accuracy be equal to or less than about ±3 to 5 μm so that the light does not fail to strike the 45-degree mirror.
In order to suppress optical losses caused by the 45-degree mirror as much as possible, it is desirable that an angle of an optical path between the core and the optical component relative to the core be almost exactly 90-degree. For this purpose, it is desirable that there be no inclination of the component (mounting inclination).
Regarding the above-described active alignment, in a known technique, a sucked component is brought into contact with a power supply member, thereby supplying power to the component so as to cause the component to emit light (see, for example, Japanese Laid-open Patent Publication No. 2003-188451, International Publication Pamphlet No. WO 2005/029658, and Japanese Laid-open Patent Publication No. 2011-9654).
There also is a known technique, in which power is supplied to a light emitting element with a mounting tool used for suction, a probe, and the like (see, for example, Japanese Laid-open Patent Publication No. 2002-9380).
In a known technique not using suction, active alignment is performed by supplying power to an optical element through a clamp that holds a sub-mount, in which the optical element is placed (see, for example, Japanese Laid-open Patent Publication No. 2005-285889).
In order to realize high positional accuracy of an optical component relative to a board, in a known method, a light emitting optical component is placed, for example, by a flip chip bonder having a capability of placing a component with high placement positional accuracy. In a flip chip bonder, the optical component is uniformly pressed at its upper surface. This allows the horizontality of the optical component to be maintained to some degree. However, in order to achieve, for example, a positional accuracy of 3 to 5 μm, which is a desirable value for an optical interconnect, the flip chip bonder does not necessarily have capability sufficient to satisfy the above-described desirable value. Furthermore, also in the flip chip bonder, when a joining material is solidified, it is desirable that the optical axis of the optical component be determined while the optical component is held in a state in which a high horizontality of the optical component is maintained.
When a probe is brought into contact with a surface of the optical component to be sucked to a suction nozzle, a sufficient suction area is not allocated for sucking the optical component to the suction nozzle. When the suction area is not sufficiently allocated, it is difficult to apply a sufficient suction force. Furthermore, when the suction area is not sufficiently allocated, it is impossible to reliably maintain the high horizontality of the optical component due to non-uniform pressure while pressing the suction nozzle against the optical component. Nowadays, since the size of the optical component is decreasing, it becomes more difficult to allocate a sufficient suction area.
When a power supply member, for example, a probe, is brought into contact with the optical component so as supply power to the optical component, the sucked optical component may be removed due to the probe being brought into contact with the optical component. In order to avoid the removal of the sucked optical component, the probe may be slowly moved to and in contact with the optical component. However, in this case, contact operation takes time.
In a method in which the optical component is clamped by arms, it is difficult to uniformly press the optical component against the board from immediately above, and accordingly, it is difficult to obtain the horizontality of the optical component. When the optical component is secured to the board in a reflow process, the optical element becomes unclamped before joining material is solidified, that is, in a state in which the optical component is not joined to the board. In this state, in order to release the optical component from the clamp without a shift in position of the optical component, a significantly sophisticated arm and clamp mechanism is desired. When a mechanical chuck is used, placement time is increased compared to a case in which the optical component is sucked.
In an aspect of the embodiment, a placement apparatus for an optical component, a suction nozzle for an optical component, and a method of producing an electronic device are provided. With the placement apparatus, the suction nozzle, or the method, when adjusting a placement position, an optical component may be reliably sucked while light is emitted from or received by the optical component.